Designing for Manufacturing (or DFM) is a key component of an effective engineering design process. DFM means thinking ahead to a given component or assembly’s manufacturing process and making early-stage design decisions to optimize the manufacturing process based on that foresight. Contrary to what many might think, simply adding “DFM checks” or “Manufacturing preparation checklists” to your design flow is not genuine DFM. Instead, one needs to encourage constant manufacturability assessments (especially during the early design stages).
Why Is DFM Important?
DFM is important because it is how you get your idea actually made and manufactured. It involves moving your product from the prototyping stage to a manufacturing environment.
The ability to quickly scale up production for mass manufacturing is another hallmark of DFM. This significantly increases the chance of getting your product to a wider audience in the shortest amount of time. Implementing DFM processes early in the development stage ensures your design intent for your product has a perfect blend of form and function.
Four DFM Objectives to Consider
When implementing DFM proceses, consider these four objectives:
1. Results: You want to manufacture your product at the lowest cost possible, and you want your product (not just a pretty rendering or mock-up) on the market.
2. Quality: Process and material selection will help you achieve your desired product and ensure it functions properly.
3. Cost: You want to manufacture your product at the lowest cost possible without sacrificing quality.
4. Time: Get your product on the market as fast as possible. The more changes made at the end of the product design the more you risk delay.
Most manufacturers will appreciate designs that have all these parameters in place before they are handed over for production. The communication between manufacturers and designers should be constant. Afterall, as the product develops, if delays mount then the more it adds costs to the end product.
The graph below illustrates the value of having these parameters in place by showing how making changes can affect the timelines of a product. The cost of making changes at the beginning of the design process is far less expensive than making them late in the process, when all the tooling is made.
Source: NeuronicWorks Inc.
How do I start introducing DFM into my workflow?
While introducing DFM into your workflow may seem daunting, like any process change the more you encourage its use, the more it will become second nature—and your designs will improve along the way. To help make the process a little easier, we recommend these initial steps to begin incorporating DFM into your workflow.
Step 1: Define your requirements
Like all engineering design processes, everything stems from your product requirements. If this is sounding like the beginning of a typical design process... that’s because it is! The information that you normally would use to design is the same information that will drive your manufacturing decisions. DFM just tells us to consider it in a different light. When defining requirements, don’t forget to look beyond the usual function-based requirements of “What must this product do?” Instead, also consider manufacturing parameters like the rate/volume of production, intended per-part cost, alignment with surrounding assemblies, and industry/client standards.
Step 2: Select your materials and process
Material selection, from both a manufacturing and functional standpoint, is a huge milestone in your design process, however, the choice cannot be made in a vacuum. We recommend choosing both the material and the fabrication process at the same time. This simple addition to the usual thought process will force you to think about (and hopefully document) the additional considerations that come along with your given material.
Thinking of making a steel structure out of thin sheetmetal? Pause and consider the process! Think back to your manufacturing requirements. If you're looking to do production runs of tens of thousands of units per year, your design will likely include stamped components which require completely different optimizations than if you intend to make just five units a year and will use manually bent components. Thinking about welding that sheetmetal? You may want to think about warpage, or analyzing the stress in a heat-affected zone.
By remembering to define your process with your material, as you design you can keep in mind the specific nuances inherent with that manufacturing process. This allows you to make better design decisions which will pay dividends down the line.
Step 3: Reach out
Regardless of whether this is your first year in the field, or if you lost count a few decades ago, there is always more to learn. Once you have considered your requirements and chosen the material and process, reach out and talk to your suppliers and manufacturers. Often they are more than happy to speak with you about difficulties with your past designs, or lessons learned from similar products. This knowledge is invaluable, as it allows for personal growth, and exposes you to other perspectives on your creation that you may never have been exposed to. It also helps create relationships with members of your community and can lead to small design changes that pay huge dividends on the shop floor.
Don’t stop at fabrication, though. Reach out to your factory floor and assembly associates, too. Often they can help you improve your design, and give you tips on assembly order, clearances, and component supply.
Step 4: Iterate
This is the most important step. Engineering design is not a linear path, and each project is a unique cycle of progress forward and marathons back. Iteration is what helps make products truly great so remember not to get discouraged! Whenever you face a setback, always keep manufacturing in mind. Think back to your manufacturing requirements, material and process choices, outside advice, and let that guide you.
Things to keep in mind during design
While this article is mostly focused on fabrication method selection (as this critical step drives so many factors in a design) this isn’t the only thing to keep in mind as part of DFM mindset.
Here are three key things to keep in mind as you design:
1. Standardization: Attempt to keep all of your components stock, wherever possible. This makes everything from design to purchasing easy and saves expensive (and slow) custom tooling and processes. In addition, work with your engineering department and create internal design standards so that designs can be reused or repurposed easily.
2. Joining: It is easy to get complacent when it comes to joining methods, but the screws, fasteners, and adhesives you choose will affect every single part produced. Consider ways to create interlocks, tabs, and clips so that you avoid the additional component. It goes beyond the cost of the fastener itself—the reduction of a part on the BOM yields savings in time, logistics, storage, and even purchasing.
46 parts
7 different parts
Tools required for assembly
2 parts
3 manufacturing processes
No tools required
Source: NeuronicWorks Inc.
3. Tolerances: Pay very close attention to the specified tolerances on your drawings. It can be tempting to put a tight tolerance if you are unsure or if there is no guideline. However, doing so will increase the cost of tooling, maximize lead time, and cause a higher defect rate. Always ensure your tolerances are as loose as possible (but no looser).
We hope this quick guide on introducing design for manufacturing into your workflow has been helpful and that you’re able to begin incorporating DFM into your workflows. This article is the first in an on-going series of deep dives into what to look for in different materials and processes so keep checking back for new entries.
If you’re looking for a design firm that implements DFM into every project then be in touch with NeuronicWorks today to discuss your design and manufacturing needs.